304 vs. 316 stainless steel: what’s the difference?
Both are part of the austenitic family of stainless steels, sharing a similar chemical composition. While this means many of their attributes are the same, there’s also a distinct difference. In this guide, we’ll look at the content of those two stainless steel grades and their unique properties – and how both express themselves in terms of characteristics: 304 vs. 316 stainless steel strength, 304 vs. 316 stainless steel uses. We’ll cover:
What is 304 stainless steel?
304 stainless steel alloys consist of at least 18% chromium and between 8% to 10.5% nickel, with a carbon content capped at 0.08%.
Austenitic stainless steels, in general, are characterized by their substantial chromium and nickel content, which imparts excellent corrosion resistance. Chromium contributes to forming a protective oxide layer, while nickel enhances the material's toughness and ductility, making it more workable. Compared to ferritic stainless steel, austenitic stainless steel contains less iron, rendering it typically non-magnetic, though some variants may exhibit slight magnetic properties.
304 stainless steel, in particular, is the most commonly used type of stainless steel due to its advantageous properties. It offers excellent resistance to a wide range of environmental conditions and corrosive agents, making it suitable for various applications, including kitchen equipment, chemical containers, and architectural paneling. The material's versatility and ease of fabrication also make 304 stainless steel a preferred choice in the food and beverage industry, healthcare facilities, and residential settings. Its ability to maintain structural integrity under high temperatures further extends its use to industrial and engineering projects. Overall, the combination of durability, corrosion resistance, and workability makes 304 stainless steel an essential material in many sectors.
You can learn more about stainless steel in our guide:
Compare 304 stainless steel with other grades in our expert guides:
| Industry | Typical applications | Why |
|---|---|---|
| Food processing equipment | Tanks, pipes & containers | Resistance to corrosion, easy to clean |
| Consumer appliances | Sinks, refrigerators, dishwashers | Durability, resistance to corrosion, aesthetic appeal |
| Automotive | Exhaust systems, trim & grilles | Resistance to corrosion, aesthetic appeal |
| Medical equipment | Surgical instruments, dental instruments & implants | Biocompatibility, resistance to corrosion & withstands high-temperature cleaning processes |
| Chemical processing equipment | Reactors, tanks & pipelines | Resistance to corrosion, stands up to a range of chemicals |
| Aerospace components | Aircraft structures, engines | High strength-to-weight ratio, resistance to corrosion, thermal stability |
Find out more about the role of stainless steel in healthcare.
304 stainless steel is also used in different types of small components. Just some examples include:
T-handle – 304 stainless steel cam
Paddle latch – 304 stainless steel screws
Torque hinge – 304 stainless steel pins & nuts
What is 316 stainless steel?
Grade 316 is another austenitic stainless steel. As part of the 300 series of austenitic stainless steel, it also contains nickel, just as 304 does. Where 304 stainless steel alloys have a minimum of 18% chromium, 316 stainless steel has less with 16%. The nickel content in 316 is also higher, at 10%.
You would think this would give 304 stainless steel a higher resistance to corrosion, but 316 contains 2% molybdenum. The molybdenum helps resist corrosion caused by chlorides, such as sea water and de-icing salts. It also gives 316 greater resistance to chemical attacks.
While each offers excellent corrosion resistance, 316 stainless steel’s is actually higher than grade 304 stainless steel. Grade 316 often exhibits better strength at high temperatures, although both have excellent heat resistance.
Grade 304 vs. 316 stainless steel appearance is impossible to judge by the naked eye – they look the same, except when it comes to cost. Expect to pay more for 316, which is due to the higher nickel content and addition of molybdenum.
What is 316 stainless steel used for?
304 vs. 316 stainless steel uses often comes down to budget. Grade 316 can be used for the same applications as 304 – as you’ll see below – but 304 can’t always be used instead of 316. Here are just some of the industries and applications where 316 is put to work.
| Industry | Typical applications | Why |
|---|---|---|
| Food processing equipment | Tanks, pipes & containers | Non-reactive – does not impart any unwanted flavors or odors to food & easy to clean |
| Oil and gas | Pipelines, valves & fittings | Resistance to corrosive fluids and gases |
| Energy/power generation | Turbine blades | High-temperature strength & corrosion resistant |
| Medical equipment | Surgical instruments, dental instruments & implants | Biocompatibility, corrosion resistant & withstands high-temperature cleaning processes |
| Chemical processing equipment | Production of organic acids, storage tanks & reactors | Molybdenum enhances corrosion resistance, high-temperature strength |
| Marine | Boat fittings & seawater piping | Highly corrosion resistant in marine environments |
316 stainless steel is considered marine grade, so can be used in some marine applications, but it’s not resistant to warmer sea water (304, even less so), which can cause chloride pitting. Still, its characteristics make it popular for use in small components too. Examples of common applications include:
Elematic 2-Lock™ cable tie – 316 stainless steel teeth
Quarter-turn spring latch
304 vs. 316 stainless steel properties
As austenitic materials, their properties are similar. In the case of 304 vs. 316 stainless steel properties, they’re identical or nearly the same, which comes down to their similar chemical composition. For instance, their densities are often the same, despite the addition of molybdenum to 316. However, molybdenum has a relatively low atomic weight, so it doesn’t have much of an impact on density.
This table shows the key differences between the two grades, including their density, melting point (or melting range for 316 grade), modulus of elasticity, electrical resistibity, thermal conductivity and shear modulus.
304 vs. 316 stainless steel: a comparison
Let’s compare their content. Again, note that they share much of the same content – except for molybdenum. Grade 316 also has more nickel, while 304 has more chromium.
| Element | 304 stainless steel % | 316 stainless steel % |
|---|---|---|
| Carbon | 0.07 | 0.07 |
| Chromium | 18.0 – 19.5 | 16.5 – 18.5 |
| Nickel | 8.0 – 10.5 | 10.0 – 13.0 |
| Silicon | 1.00 | 1.00 |
| Manganese | 2.00 | 2.00 |
| Phosphorous | 0.045 | 0.045 |
| Sulfur | 0.015 | 0.015 |
| Nitrogen | 0.10 | 0.10 |
| Molybdenum | - | 2.0 – 2.5 |
304 vs. 316 stainless steel strength
When it comes to mechanical strength, 316 stainless steel is generally considered stronger than 304. Again, this is attributed to 316’s molybdenum content. As a result, 316 stainless steel generally has better mechanical properties. The yield and tensile strength of each vary, depending on the manufacturing process and conditions involved – but in general, the tensile strength of 316 stainless steel is higher than that of 304 stainless steel.
Choosing between 304 and 316 stainless steel comes down to your application and its specific requirements for oxidation resistance, mechanical strength, and ultimately, cost. For example, if your application won’t be in a highly corrosive environment, go with grade 304. It’s still extremely resistant to corrosion, but it also costs less. At the same time, using 304 in applications that are better suited for 316 stainless steel can end up costing you more in the long run.
To understand the Rockwell B hardness test below, see our guide, What’s shore hardness and why should you care?
| Mechanical properties | 304 stainless steel | 316 stainless steel |
|---|---|---|
| Ultimate Tensile Strength | 73200 psi | 79800 psi |
| Tensile Yield Strength | 31200 psi | 34800 psi |
| Hardness (Rockwell B) | 70 | 80 |
| Elongation at break | 70% | 60% |
304 vs. 316 stainless steel differences
In summary, these are the primary characteristics of each stainless steel.
316 stainless steel has superior corrosion resistance properties but both are used for pharmaceutical and medical applications, including medical surgical instruments. Whilst the two grades both have high tensile strength, 316 is superior. However, 304 stainless steel has excellent welding qualities and is the most widely used of the austenitic stainless steels for such applications.
| Characteristics | 304 stainless steel | 316 stainless steel |
|---|---|---|
| Corrosion resistance | Excellent | Even better |
| Magnetic | No | No |
| Weldability | High | Good |
| Hardens during cold forming | Yes | Yes |
| Formability | Very good | Good |
| Machinability (annealed) | Fair, but better than 316 | Fair |
| Resists elevated temperatures | High | High |
| Maximum intermittent service temperature | 1562°F | 1562°F |
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